Purpose:To examine the test–retest reliability of student-administered (SA) health-related fitness tests in school settings and to compare indices of reliability with those taken by trained research-assistants.Methods:Participants (n = 86; age: 13.43 [0.33] y) were divided into 2 groups, SA (n = 45, girls = 26) or research-assistant administered (RA; n = 41, girls = 21). The SA group had their measures taken by 8 students (age: 15.59 [0.56] y, girls = 4), and the RA group had their measures taken by 8 research-assistants (age: 21.21 [1.38], girls = 5). Tests were administered twice by both groups, 1 week apart. Tests included body mass index, handgrip strength, standing broad jump, isometric plank hold, 90° push-up, 4 × 10-m shuttle run, back-saver sit and reach, and blood pressure.Results:Intraclass correlation coefficients for SA (≥.797) and RA (≥.866) groups were high, and the observed systematic error (Bland–Altman plot) between test 1 and test 2 was close to 0 for all tests. The coefficient of variation was less than 10% for all tests in the SA group, aside from the 90° push-up (24.3%). The SA group had a marginally lower combined mean coefficient of variation across all tests (6.5%) in comparison with the RA group (6.8%).Conclusion:This study demonstrates that, following familiarization training, SA health-related fitness tests in school-based physical education programs can be considered reliable.